Grand Cherokee 2WD V6-3.7L (2008)
Seat Heater Switch: Description and Operation
Description
Front Seats
DESCRIPTION
Two heated seat switches (2) for the front seats are located in the center stack of the instrument panel. These two switches allow the driver and front seat
passenger to select from two different levels of electrical seat heating (HI/LO). The front heated seat switches are an integral part of the instrument panel
lower switch pod assembly (1). If either of the switches is damaged or inoperative the complete switch pod assembly must be replaced, See: Service and
Repair/Heated Seat Switch - Removal.
When either of the front heated seat switches are depressed a resistance signal is sent to the ElectroMechanical Instrument Cluster (EMIC) (also known
as the Cab Compartment Node/CCN). The instrument cluster receives this message via the Local Interconnect Network (LIN) data bus. The instrument
cluster then sends a message via the Controller Area Network (CAN) data bus to the heated seat module, signaling the module to energize the heating
element for the selected seat.
Amber Light Emitting Diodes (LEDs) in each switch indicate the level of heat in use: Two LEDs are illuminated for high, one for low, and none for off.
Pressing the switch once will select high-level heating. Pressing the switch a second time will select low-level heating. Pressing the switch a third time
will shut the heating elements off. The switch LEDs are controlled by the instrument cluster.
The LED indicator lamps in each heated seat switch cannot be repaired. If the LED lamps are inoperative or damaged, or the switch is inoperative or
damaged the complete instrument panel lower switch pod assembly must be replaced, See: Service and Repair/Heated Seat Switch - Removal.
2nd Row
DESCRIPTION
The heated seat switches (1) for the 2nd row seats are located in the rear center floor console (2). These switches allow the 2nd row seat passengers to
select from two different levels of electrical seat heating (HI/LO). Amber Light Emitting Diodes (LEDs) in the top portion of each switch indicate the
level of heat in use: Two LEDs are illuminated for high, one for low, and none for off. Pressing the switch once will select high-level heating. Pressing
the switch a second time will select low-level heating. Pressing the switch a third time will shut the heating elements off. The 2nd row heated seat
switches are available individually for service. If the switches are inoperative or damaged in any way they should be replaced, See: Service and
Repair/Heated Seat Switch - Removal.
The two momentary, push button-type heated seat switches provide a hardwired resistance signal to the ElectroMechanical Instrument Cluster (EMIC)
(also known as the Cab Compartment Node/CCN). The instrument cluster then sends a message via the Controller Area Network (CAN) data bus
network to the heated seat module, signaling the module to energize the heating element for the selected seat. Light Emitting Diodes (LED) in each
switch indicate the level of heat in use. The switch LEDs are controlled by the instrument cluster.
The two LED indicator lamps and the incandescent bulb in each heated seat switch cannot be repaired. If the indicator lamps or back lighting bulb are
inoperative or damaged, the individual heated seat switch must be replaced.
